Establishing at the outset an excellent long lasting seal between combinations of components installed in an underground sealed liquid distribution system, has always been a prime objective. The same prime objective carries over to making repairs, changing, and extending, such underground sealed liquid distribution systems.
In the past, inventors have provided pipe seals, gaskets, and packing, which during the final positioning thereof, receive internally a liquid, which subsequently hardens, in attempting to provide long lasting seals between combinations of such components.
For example:
In 1937, John A. Byers in his U.S. Pat. No. 2,099,722, illustrated and described his pipe joint. He utilized a sealing gasket which had a cavity. He filled this cavity with a solidifiable fluid such as felted paraffine, wax, lead, or sulphur compounds. Upon the entry of the solidifiable fluid, the sealing gasket expanded to create a good seal, and the seal remained when the fluid hardened.
In 1942, Eugene Freyssinet in his U.S. Pat. No. 2,306,160 disclosed his packing device in various embodiments sealing between various components. The liquid he used as a filler was a synthetic resin, which passed from a liquid state to a solid state. The resin was called by the trademark as being "Brauthite", and was said to be a combination of formaldehyde and phenol, which hardens in the presence of air.
In 1965, Albert A. Hollingsworth, in his U.S. Pat. No. 3,222,076, disclosed his pipe joint packing. He used a gasket with an initially collapsed central cavity. Then when the gasket was located in the sealing position, he injected into this central cavity, selected epoxy fill materials, such as epichlorohydrin and bisphenol-A, which, while reacting together, entered as a liquid and then self hardened, expanding the gasket into the sealing shape and position. Other fill materials used were epoxy novolacs, polyesters, phenolics, and melamines.
In 1982, A. Eugene Martin, in his U.S. Pat. No. 4,350,351, illustrated and described his manhole joint gasket assembly and the joint formed therewith. To increase the sealing power of his gasket he surrounded the back of the gasket with a hollow ring. Then to increase the backing power of this ring, he injected a two-component foam-forming, originally liquid substance, that expanded into a solid stage under pressure in the hollow interior of this backing ring.
In 1985, John Ditcher, in his U.S. Pat. No. 4,508,355 disclosed his gasket suitable for use in sealing the exterior of sewer pipe to an opening in a manhole, and the method and system employing the same. His circumferential gasket in various embodiments was fitted to a specially formed circular receiving volume, located in the well of the manhole, about the hole through which the end of a sewer pipe was inserted. When required, to insure an adequate seal would be maintained by the gasket, Mr. Ditcher filled a cavity in the gasket, after the positioning thereof, with an expandable filler, by using a hypodermic like syringe.
The accomplishments of these prior inventors are recognized; however, there remained a need for improved pipe seals, incorporating solidifiable liquids, which could be used throughout underground sealed liquid distribution systems to create excellent seals between combinations of many components of many different types, materials, and sizes, which often also have irregular surfaces, shapes, and sizes, and which often must remain misaligned, yet withstand high pressures.